The problem is the database has been moved to a new server, so I need to update the connection strings; I can change the the datasource for the main layer and reconnect fine; however unless the database is there, the join connection information is blank.

i.e. the IDisplayTable.DisplayTable is null....

Is there any other method of reading what the Joins are on a layer, when the layer is not valid? For example the Invalid layer still has it's original IWorkspaceName so I change change the server name, but nothing for the join